[SLUG] different from address for different lists?

[Dave Fitch <davidf@xxxxxxxxxxxxxxxx>]

while there's a spate of mutt questions...
how can I set a different outgoing email address for
different mailing lists?

I use mutt and have each list in a different mail file.
Mutt supposedly sets my "From:" address and
other headers (like Reply-To: etc) but postfix writes
a "From" header (set in the "canonical" file) onto
outgoing emails also, otherwise people get to see two
different email addresses for me.

Ta,
Dave.